Field of the Invention
The present invention relates to a solid-state imaging apparatus and driving method therefor as well as to an imaging system equipped with the solid-state imaging apparatus.
Description of the Related Art
Solid-state imaging apparatus adapted to acquire color images widely use a method which acquires color information using a single panel on which color filters having spectral characteristics of transmitting lights in wavelength bands corresponding, for example, to green, red, and blue are arrayed on a pixel by pixel basis.
With the pixels (imaging elements) on which color filters are arrayed, since the color filters of different colors differ in transmittance, the sensitivity of the pixels (imaging elements) varies from color to color. Therefore, when the pixels are driven for a same charge accumulation period, the charge accumulation period may be optimal for the pixels equipped with a certain color filter, but may not necessarily be optimal for pixels equipped with another color filter.
Japanese Patent Application Laid-Open No. 2008-219830 discloses an imaging apparatus in which pixels of different colors are driven for different accumulation periods such that the accumulation periods will coincide in center position with one another. The imaging apparatus is characterized in that accumulation start time and accumulation end time for color pixels are varied among green, red, and blue colors so as to make the accumulation periods coincide in center position. Consequently, image signal outputs of different colors are caused to coincide in magnitude, thereby reducing color bleeding when a moving object is photographed.
However, with the conventional technique, because intervals of image signal outputs are identical among different colors, if image signal output intervals are extended to increase outputs of blue and red pixels lower in sensitivity than green pixels, the image signal output intervals are extended not only for the blue and red pixels, but also for the green pixels higher in sensitivity. This poses a problem in that a resolution deteriorates in a time direction, making blurring conspicuous on moving images.
The present invention has been made in view of the above problem and has an object to provide a setup for keeping a resolution of color motion imaging at a high level in a time direction and thereby improving quality of moving images.